Ошибка при отмене сохранения файла через SaveFileDialog - Visual Basic .NET

' Create Word Application
        Dim oWord As Word.Application = DirectCast(CreateObject("Word.Application"), Word.Application)
 
        ' Create new word document
        Dim oDoc As Word.Document = oWord.Documents.Add()
        oWord.Visible = False
 
        oDoc.Range.InsertAfter(Label1.Text)
        oDoc.Range.InsertParagraphAfter()
 
        Dim headers = (From ch In Grid1.Columns _
                      Let header = DirectCast(DirectCast(ch, DataGridViewColumn).HeaderCell, DataGridViewColumnHeaderCell) _
                      Select header.Value).ToArray()
        Dim headerText() As String = Array.ConvertAll(headers, Function(v) v.ToString)
 
        Dim items() = (From r In Grid1.Rows _
              Let row = DirectCast(r, DataGridViewRow) _
              Where Not row.IsNewRow _
              Select (From cell In row.Cells _
                  Let c = DirectCast(cell, DataGridViewCell) _
                  Select c.Value).ToArray()).ToArray()
 
        Dim table As String = String.Join(vbTab, headerText) & Environment.NewLine
        For Each a In items
            Dim t() As String = Array.ConvertAll(a, Function(v) v.ToString)
            table &= String.Join(vbTab, t) & Environment.NewLine
        Next
        table = table.TrimEnd(CChar(Environment.NewLine))
        Clipboard.SetText(table)
 
        Dim oTable As Word.Table = oDoc.Tables.Add(oDoc.Bookmarks.Item("\endofdoc").Range, items.Count + 1, headers.Count)
        oTable.Range.Paste()

'сохранение файла
        Dim sd As New SaveFileDialog
        sd.Filter = "Документ Word(*.docx)|*.docx"
        sd.FileName = Label1.Text
        If sd.ShowDialog = System.Windows.Forms.DialogResult.OK Then
            oDoc.SaveAs(sd.FileName)
        End If
 
        oDoc.Close()
        oWord.Quit()
 
        'уничтожаем объект - документ
        oDoc = Nothing
        'уничтожаем объект - Word
        oWord = Nothing